No cache version.
Caching disabled. Default setting for this page:enabled (code DEF204)If the display is too slow, you can disable the user mode to view the cached version.
Rechercher dans le manuel MySQL
15.19.4 InnoDB memcached Multiple get and Range Query Support
The daemon_memcached
plugin supports multiple
get operations (fetching multiple key-value pairs in a single
memcached query) and range queries.
Multiple get Operations
The ability to fetch multiple key-value pairs in a single
memcached query improves read performance by
reducing communication traffic between the client and server. For
InnoDB
, it means fewer transactions and
open-table operations.
The following example demonstrates multiple-get support. The
example uses the test.city
table described in
Creating a New Table and Column Mapping.
- +---------+-----------+-------------+---------+-------+------+--------+
- | city_id | name | state | country | flags | cas | expiry |
- +---------+-----------+-------------+---------+-------+------+--------+
- +---------+-----------+-------------+---------+-------+------+--------+
Run a get
command to retrieve all values from
the city
table. The results are returned in a
key-value pair sequence.
telnet 127.0.0.1 11211
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
get B C D H M
VALUE B 0 22
BANGALORE|BANGALORE|IN
VALUE C 0 21
CHENNAI|TAMIL NADU|IN
VALUE D 0 14
DELHI|DELHI|IN
VALUE H 0 22
HYDERABAD|TELANGANA|IN
VALUE M 0 21
MUMBAI|MAHARASHTRA|IN
END
When retrieving multiple values in a single get
command, you can switch tables (using
@@
notation) to retrieve the value for the first key, but you cannot
switch tables for subsequent keys. For example, the table switch
in this example is valid:
containers.name
get @@aaa.AA BB
VALUE @@aaa.AA 8 12
HELLO, HELLO
VALUE BB 10 16
GOODBYE, GOODBYE
END
Attempting to switch tables again in the same
get
command to retrieve a key value from a
different table is not supported.
Range Queries
For range queries, the daemon_memcached
plugin
supports the following comparison operators:
<
, >
,
<=
, >=
. An operator
must be preceded by an @
symbol. When a range
query finds multiple matching key-value pairs, results are
returned in a key-value pair sequence.
The following examples demonstrate range query support. The
examples use the test.city
table described in
Creating a New Table and Column Mapping.
- +---------+-----------+-------------+---------+-------+------+--------+
- | city_id | name | state | country | flags | cas | expiry |
- +---------+-----------+-------------+---------+-------+------+--------+
- +---------+-----------+-------------+---------+-------+------+--------+
Open a telnet session:
telnet 127.0.0.1 11211
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
To get all values greater than B
, enter
get @>B
:
get @>B
VALUE C 0 21
CHENNAI|TAMIL NADU|IN
VALUE D 0 14
DELHI|DELHI|IN
VALUE H 0 22
HYDERABAD|TELANGANA|IN
VALUE M 0 21
MUMBAI|MAHARASHTRA|IN
END
To get all values less than M
, enter
get @<M
:
get @<M
VALUE B 0 22
BANGALORE|BANGALORE|IN
VALUE C 0 21
CHENNAI|TAMIL NADU|IN
VALUE D 0 14
DELHI|DELHI|IN
VALUE H 0 22
HYDERABAD|TELANGANA|IN
END
To get all values less than and including M
,
enter get @<=M
:
get @<=M
VALUE B 0 22
BANGALORE|BANGALORE|IN
VALUE C 0 21
CHENNAI|TAMIL NADU|IN
VALUE D 0 14
DELHI|DELHI|IN
VALUE H 0 22
HYDERABAD|TELANGANA|IN
VALUE M 0 21
MUMBAI|MAHARASHTRA|IN
To get values greater than B
but less than
M
, enter get @>B@<M
:
get @>B@<M
VALUE C 0 21
CHENNAI|TAMIL NADU|IN
VALUE D 0 14
DELHI|DELHI|IN
VALUE H 0 22
HYDERABAD|TELANGANA|IN
END
A maximum of two comparison operators can be parsed, one being
either a 'less than' (@<
) or 'less than or
equal to' (@<=
) operator, and the other
being either a 'greater than' (@>
) or
'greater than or equal to' (@>=
) operator.
Any additional operators are assumed to be part of the key. For
example, if you issue a get
command with three
operators, the third operator (@>C
) is
treated as part of the key, and the get
command
searches for values smaller than M
and greater
than B@>C
.
get @<M@>B@>C
VALUE C 0 21
CHENNAI|TAMIL NADU|IN
VALUE D 0 14
DELHI|DELHI|IN
VALUE H 0 22
HYDERABAD|TELANGANA|IN
Can not display this page of the Infobrol website
Type of error (18-01)
Unknown format specifier "&"Please try again in a few minutes…
Steph